Receptor steric hindrance immunoassay for receptor determination

Abstract

A method is provided for the determination of receptors, particularly antibodies, where a polyepitopic reagent is employed, at least one of the epitopes being specific for the receptor of interest. The epitopic sites are situated on the reagent, so that the binding of the receptor of interest to the reagent will sterically hinder binding of receptors other than the receptor of interest. In carrying out the assay, the sample suspected of containing the receptor of interest, the reagent, and a predetermined amount of receptors for the other epitopes are combined. Because of the steric inhibition to the simultaneous binding of the two different receptors, the amount of receptor of interest bound to the reagent will affect the amount of the other receptor which becomes bound to the reagent. By analyzing directly or indirectly for the amount of the receptor which is added in a predetermined amount, and comparing the results to known standards, qualitative or quantitative determinations of the amount of receptor of interest may be made. Various detector systems may be employed for determining the amount of the receptor of interest which is present in the unknown sample. The systems include stable free radicals, enzymes, radioactive labels, fluorescers, and the like.